State Key Laboratory of Water Environment Simulation, School of Environment, Beijing Normal University, Beijing 100875, China.
Environ Sci Technol. 2010 Dec 1;44(23):9150-6. doi: 10.1021/es100886r. Epub 2010 Oct 14.
The virtual water strategy which advocates importing water intensive products and exporting products with low water intensity is gradually accepted as one of the options for solving water crisis in severely water scarce regions. However, if we count the virtual water embodied in imported products as the water saved for a region, we might overestimate the saving by including the virtual water that is later re-exported in association with the proceeded products made from the originally imported products. This problem can be avoided by accounting for the saved water through calculating water footprint (WF) in domestic final consumptive products. In this paper, an input-output analysis (IOA) based on the water footprint accounting framework is built to account for WF and virtual water trade of final consumptive products in the water stressed Haihe River basin in China for the year 1997, 2000, and 2002. The input-output transaction tables of the three years are constructed. The results show WF of 46.57, 44.52, and 42.71 billion m(3) for the three years, respectively. These volumes are higher than the water used directly in the corresponding years in the basin. A WF intensity (WFI) indicator is then used to assess if the economic activities in the basin are consistent with the virtual water strategy. The temporal change of the WFI is also decomposed by the index number analysis method. The results showed that the basin was silently importing virtual water through the trade of raw and processed food commodities under the background of the whole economic circulation.
虚拟水战略提倡进口耗水产品和出口低耗水产品，逐渐被视为严重缺水地区解决水危机的选择之一。然而，如果我们将进口产品中所包含的虚拟水视为一个地区的节水，那么我们可能会高估这种节约，因为其中包括了与最初进口产品相关的加工产品再次出口所涉及的虚拟水。这个问题可以通过计算国内最终消费产品的水足迹（WF）来避免，即将虚拟水贸易包含在内。本文构建了一个基于水足迹核算框架的投入产出分析（IOA），以核算 1997 年、2000 年和 2002 年中国水资源紧张的海河流域最终消费产品的 WF 和虚拟水贸易。构建了这三年的投入产出交易表。结果表明，这三年的 WF 分别为 465.7 亿立方米、445.2 亿立方米和 427.1 亿立方米。这些水量高于流域相应年份直接用水量。然后使用 WF 强度（WFI）指标来评估流域经济活动是否符合虚拟水战略。还通过指数分析方法对 WFI 的时间变化进行了分解。结果表明，在整个经济循环的背景下，流域通过原材料和加工食品商品的贸易，正在默默地进口虚拟水。
